The DCS function - Documentation for BMC AMI Ops Automation for Batch ThruPut 22.4

This topic describes the functions provided by the Component Dataset Contention Services.

The Dataset Contention Services Component

BMC ThruPut Manager offers a Component that is installed on top of the BMC ThruPut Manager Base Product. The Component is named “Dataset Contention Services”, or DCS for short. It provides a complete solution to the automation of the data set contention resolution process. This topic introduces the different functions provided by this package.

Functions Provided With DCS

This Component provides the following additional functions:

Job Action Language extensions for DCS.
DAL—A Detail Action Language particularly suited for DD/data set processing.
Dataset Contention and Repossessing Services.
ALERT Services.
NAGGING Services.
Dataset Disposition ALTER Services.
Dataset Reservation
JECL Service Extensions.
Dataset Contention Reports.
User Exit.
Addition of a DCS Display to the User Display Facility.
File Definition Services Extensions.

Job Action Language (JAL) Extensions for DCS

Extensions to JAL are provided to support DCS. They allow you to instruct DCS for job related actions. For specific DD/data set requests, DAL is used.

A detailed description of the JAL extensions is found in the DAL/JAL User Guide and JAL Reference publications.

Detail Action Language— DAL

A Detail Action Language, similar to JAL, is provided to define rules and request DCS actions at the DD/data set level.

A complete set of supporting facilities to load, refresh, and trace DAL is also provided.

A detailed description of DAL is provided in the publications DAL/JAL User Guide and DAL Reference.

Dataset Contention and Repossessing Services

Complete automation facilities are provided to help you manage jobs that must be delayed because of data set contention. The DCS application provides:

Complete automation of the holding and releasing of jobs.
A separate hold reason for jobs awaiting data sets.
An implementation of the concept of data set service level. This allows you to control which jobs are to receive priority when data sets become available.
Facilities to repossess data sets automatically from TSO users.
Operator Commands.
JAL/DAL interfaces.
JECL interfaces.

With the above facilities, you have both automation and control of your data set contention resolution process.

Note

If DCS is installed and enabled in your system, all jobs are managed for data set contention, including any jobs submitted in an Exempt class.

A detailed description of the data set service level and repossessing facilities is included in Requesting Dataset Service Levels.

The Operator commands are described in the Operating space.

Nagging Services

DCS provides a mechanism to nag TSO users that are holding data sets needed for a job. This facility is called—what else?—NAG services. The following controls are provided:

You can modify the second line of the NAG to reflect whatever text you want.
You can decide which user or group of users are nagged.
You can also suppress nagging to a user or users.
You can request the nagging frequency.
You can indicate how many times users are nagged.

You can combine any of the above options to fine-tune nagging to cover practically any situation. A detailed description of Nagging Services is found in Nagging.

ALERT Services

The ALERT Service provides you with a facility to notify a group, such as Production Control, when a job has been held for more than a specified number of minutes because of data set contention.

DCS does not produce ALERTs unless it is instructed to do so. You can control:

Whether or not an ALERT is generated for a job.
Header and Trailer text for ALERTs.
The interval time before the ALERT is produced.
The destination of an ALERT.

The mechanism to produce, spool, and print ALERTs is the same mechanism BMC ThruPut Manager uses for Volume Lists.

A detailed description of ALERT Services is found in “Alerting" section.

Dataset Disposition Alteration Services

With DCS, you can analyze the usage of the first disposition parameter for each DD statement that is associated with a permanent data set. Depending on what you find, you can instruct DCS to take one of the following actions:

Fail/warn the job.
Alter the disposition for that DD statement.

The disposition alteration is for data set enqueueing purposes.

Requests to DCS to alter the disposition are done at the DD statement level. All the relevant information about the job and the particular DD statement is available to you. As a result, you can provide very specific rules for the ALTERation of the first parameter of the DISP keyword.

A detailed description of Dataset Disposition Alteration Services is found in Altering Dataset Disposition.

Dataset Reservation

DCS can eliminate certain job failures and volume contention problems by ENQing during job initiation on the real data set name for GDGs and data sets referred to by aliases. At that time, if there is a conflict the job can be requeued. Once Dataset Reservation support is activated, it automatically applies to all jobs. If necessary, you can turn off this service for individual jobs through the JAL statement DCS SET.

For more discussion of Dataset Reservation and how to implement it, see Altering Dataset Disposition.

JECL Services Extensions

DCS can also be instructed with JECL statements. JECL services give your installation the opportunity to “distribute” DCS facilities to your users.

It is important to realize that your installation does not lose control by “outboarding” these facilities. JAL and DAL allow you to determine whether or not a job has DCS control statements and the type of statement. As a result, you can allow job submitters to use as much or as little functionality as desired. If the job submitter is not allowed to use a particular capability, you can generate an informative message and fail the job.

The JECL facilities available are documented in the JECL Reference Guide.

DCS Reporting

DCS collects all the necessary information to be able to produce, on request, two types of reports:

One report gives you information on jobs that were delayed. It shows how many times the job was delayed, the number of minutes that the job was delayed waiting for data sets, and the data sets that were involved.
The other report gives you information on data sets that cause contention problems. The number of minutes that the data set was in contention are shown, together with the jobs affected and the holders of the data set.

Both reports together give you a complete picture of the problem: the jobs that were affected, the data sets that were involved, and the holders of the data sets.

The reporting system allows selection criteria. For example, you can request that only jobs that “experience a 20-minute delay or more” be shown.

For DCS to collect data in contention situations, you must:

Request recording for the job in JAL.
Activate the recording file with a TMSS initialization statement.

The Dataset Contention Reporting Facilities are documented in The Dataset Contention Reporting System.

UDF Extensions For DCS

If the User Display Facility shows the DCS acronym for a job, a user can select that acronym and open the DCS Window. A sample DCS Window is shown here.

The first line of the DCS Window is the Information Summary Line for the job.

Subsequent lines describe each data set that the job requires but cannot yet allocate because of data set contention. The data set name is shown, accompanied by the level of service requested.

A job analyzer exit is provided to inspect JECL statements. This exit is Exit 19 and is fully documented in the Exits: System Programming Guide publication.

File Definition Services Extensions

DCS needs one mandatory file, and depending on the options, two other files:

The Control File. This file is mandatory.
The SPOOL File. This file is needed if you want to generate ALERTs using Console Printing Services.
The CMF File. This file is needed if you want DCS to generate management reporting data when data set contention occurs.

These files are documented in Base Product: System Programming space in File Definition Services (FDS) Function section.